DESCRIPTION Pancreatic cancer is the fifth leading cause of death from cancer in the United States with the majority patients presenting with advanced disease. Consequently, only a small percentage of patients have resectable tumors and the median survival is measured in months. Even among patients who have resectable disease, the majority of these patients have tumor recurrence within one or two years despite post-operative radiation therapy, chemotherapy or combined radiation and chemotherapy. Clinical phase I and II trials of gemcitabine alone have been completed or underway in a variety of solid tumors using several different schedules. This protocol will test the feasibility of concurrent gemcitabine and ionizing radiation in a cohort of patients with locally advanced, pancreatic cancer. These specific aims are to assess the time to disease progression and overall survival in patients with locally advanced pancreatic cancer and to evaluate the quality of life in patients receiving therapy. In completed phase I studies, gemcitabine was found to be active against a variety of tumors including breast, colon, cervical, non-small cell lung cancer and pancreas. Several phase II trials are currently underway, most of them exploring the weekly bolus schedule. Preclinical in vitro data suggests the gemcitabine has activity as a radiosensitizer in pancreatic tumor cell lines.